Yes, that is correct. ti_onweapon_attack is the check interval. snd_pistol_shot resolves to SOUNDbattle.ogg. Unfortunately, the sound names are not used in sound.txt so the editor can't resolve back to the originals, it can only give the filename.
Although the if is wrong. Looks like conditions aren't operations below 10000 anymore. Not sure when I'll get those fixed, probably when all the operations are more fully documented.